tyeth · tyeth · Aug 26, 2026 · Aug 26, 2026 · Aug 26, 2026 · Aug 26, 2026
diff --git a/ports/espressif/Makefile b/ports/espressif/Makefile
@@ -848,6 +848,9 @@ ifneq ($(CIRCUITPY_BLEIO_NATIVE),0)
 endif
 
 SDKCONFIGS := esp-idf-config/sdkconfig.defaults;$(DEBUG_SDKCONFIG);$(FLASH_SIZE_SDKCONFIG);$(FLASH_MODE_SDKCONFIG);$(FLASH_SPEED_SDKCONFIG);$(PSRAM_SDKCONFIG);$(PSRAM_SIZE_SDKCONFIG);$(PSRAM_MODE_SDKCONFIG);$(PSRAM_SPEED_SDKCONFIG);$(BLE_SDKCONFIG);$(TARGET_SDKCONFIG);boards/$(BOARD)/sdkconfig
+ifneq ($(EXTRA_SDKCONFIG),) # CP-WIFI-DEBUG
+	SDKCONFIGS := $(SDKCONFIGS);$(EXTRA_SDKCONFIG)
+endif
 
 # create the config headers
 .PHONY: do-sdkconfig

diff --git a/ports/espressif/common-hal/espnow/ESPNow.c b/ports/espressif/common-hal/espnow/ESPNow.c
@@ -19,6 +19,10 @@
 
 #include "esp_now.h"
 #include "mphalport.h"
+#include "esp_wifi.h" /* CP-WIFI-DEBUG */
+#include "esp_log.h" /* CP-WIFI-DEBUG */
+#include "esp_heap_caps.h" /* CP-WIFI-DEBUG */
+static const char *TAG = "CP espnow"; /* CP-WIFI-DEBUG */
 
 #include "esp_now.h"
 
@@ -120,7 +124,18 @@ void common_hal_espnow_init(espnow_obj_t *self) {
         common_hal_wifi_radio_set_enabled(&common_hal_wifi_radio_obj, true);
     }
 
-    CHECK_ESP_RESULT(esp_now_init());
+    { /* CP-WIFI-DEBUG */
+        wifi_mode_t m = 0; uint8_t ch = 0; wifi_second_chan_t sc = 0;
+        esp_wifi_get_mode(&m); esp_wifi_get_channel(&ch, &sc);
+        ESP_LOGW(TAG, "esp_now_init: before mode=%d ch=%d/%d", m, ch, sc);
+    }
+    esp_err_t now_res = esp_now_init();
+    {
+        wifi_mode_t m = 0; uint8_t ch = 0; wifi_second_chan_t sc = 0;
+        esp_wifi_get_mode(&m); esp_wifi_get_channel(&ch, &sc);
+        ESP_LOGW(TAG, "esp_now_init -> 0x%x: after mode=%d ch=%d/%d", now_res, m, ch, sc);
+    }
+    CHECK_ESP_RESULT(now_res);
 
     // esp_now_set_peer_rate_config() is poorly documented, and we haven't figured out
     // what the esp_now_rate_config_t settings should be. For now, just ignore phy_rate.
@@ -178,6 +193,10 @@ mp_obj_t common_hal_espnow_send(espnow_obj_t *self, const mp_buffer_info_t *mess
            (mp_hal_ticks_ms() - start) <= DEFAULT_SEND_TIMEOUT_MS) {
         RUN_BACKGROUND_TASKS;
     }
+    { /* CP-WIFI-DEBUG */
+        ESP_LOGW(TAG, "esp_now_send len=%u -> 0x%x (waited %lu ms) idf_free=%u largest=%u internal_free=%u", (unsigned)message->len, err, (unsigned long)(mp_hal_ticks_ms() - start),
+            (unsigned)heap_caps_get_free_size(MALLOC_CAP_8BIT), (unsigned)heap_caps_get_largest_free_block(MALLOC_CAP_8BIT), (unsigned)heap_caps_get_free_size(MALLOC_CAP_INTERNAL));
+    }
     CHECK_ESP_RESULT(err);
 
     return mp_const_none;

diff --git a/ports/espressif/common-hal/wifi/Radio.c b/ports/espressif/common-hal/wifi/Radio.c
@@ -25,6 +25,8 @@
 
 #include "components/esp_netif/include/esp_netif_net_stack.h"
 #include "components/esp_wifi/include/esp_wifi.h"
+#include "components/log/include/esp_log.h" /* CP-WIFI-DEBUG */
+static const char *TAG = "CP wifi"; /* CP-WIFI-DEBUG */
 #include "components/lwip/include/apps/ping/ping_sock.h"
 #include "lwip/sockets.h"
 
@@ -269,14 +271,21 @@ void common_hal_wifi_radio_start_ap(wifi_radio_obj_t *self, uint8_t *ssid, size_
 
     config->ap.max_connection = max_connections;
 
-    esp_wifi_set_config(WIFI_IF_AP, config);
+    esp_err_t cfg_res = esp_wifi_set_config(WIFI_IF_AP, config); /* CP-WIFI-DEBUG */
+    {
+        wifi_mode_t m = 0; uint8_t ch = 0; wifi_second_chan_t sc = 0;
+        esp_wifi_get_mode(&m); esp_wifi_get_channel(&ch, &sc);
+        ESP_LOGW(TAG, "start_ap ssid='%s' req_ch=%d auth=%d maxconn=%d -> set_config=0x%x mode=%d cur_ch=%d/%d",
+            (char *)config->ap.ssid, channel, esp_authmode, max_connections, cfg_res, m, ch, sc);
+    }
     // Wait a few ms for the AP to start. Empirically, this takes < 3ms on ESP32, and < 1ms on other chips.
     for (size_t ms = 0; ms < 10; ms++) {
         if (common_hal_wifi_radio_get_ap_active(self)) {
             break;
         }
         mp_hal_delay_ms(1);
     }
+    ESP_LOGW(TAG, "start_ap done: ap_active=%d netif_up=%d", common_hal_wifi_radio_get_ap_active(self), esp_netif_is_netif_up(self->ap_netif)); /* CP-WIFI-DEBUG */
 }
 
 bool common_hal_wifi_radio_get_ap_active(wifi_radio_obj_t *self) {
@@ -614,11 +623,14 @@ void common_hal_wifi_radio_stop_dhcp_client(wifi_radio_obj_t *self) {
 }
 
 void common_hal_wifi_radio_start_dhcp_server(wifi_radio_obj_t *self) {
-    esp_netif_dhcps_start(self->ap_netif);
+    esp_err_t r = esp_netif_dhcps_start(self->ap_netif); /* CP-WIFI-DEBUG */
+    esp_netif_dhcp_status_t st = 0; esp_netif_dhcps_get_status(self->ap_netif, &st);
+    ESP_LOGW(TAG, "dhcps_start -> 0x%x status=%d", r, st);
 }
 
 void common_hal_wifi_radio_stop_dhcp_server(wifi_radio_obj_t *self) {
-    esp_netif_dhcps_stop(self->ap_netif);
+    esp_err_t r = esp_netif_dhcps_stop(self->ap_netif); /* CP-WIFI-DEBUG */
+    ESP_LOGW(TAG, "dhcps_stop -> 0x%x", r);
 }
 
 void common_hal_wifi_radio_set_ipv4_address(wifi_radio_obj_t *self, mp_obj_t ipv4, mp_obj_t netmask, mp_obj_t gateway, mp_obj_t ipv4_dns) {

diff --git a/ports/espressif/common-hal/wifi/__init__.c b/ports/espressif/common-hal/wifi/__init__.c
@@ -24,6 +24,7 @@
 wifi_radio_obj_t common_hal_wifi_radio_obj;
 
 #include "components/log/include/esp_log.h"
+#include "esp_mac.h" /* CP-WIFI-DEBUG */
 
 #include "supervisor/port.h"
 #include "supervisor/workflow.h"
@@ -75,10 +76,16 @@ static void event_handler(void *arg, esp_event_base_t event_base,
             case WIFI_EVENT_AP_STOP:
                 ESP_LOGW(TAG, "ap stop");
                 break;
-            case WIFI_EVENT_AP_STACONNECTED:
+            case WIFI_EVENT_AP_STACONNECTED: { /* CP-WIFI-DEBUG */
+                wifi_event_ap_staconnected_t *e = (wifi_event_ap_staconnected_t *)event_data;
+                ESP_LOGW(TAG, "ap sta connected " MACSTR " aid=%d idf_free=%u largest=%u", MAC2STR(e->mac), e->aid, (unsigned)heap_caps_get_free_size(MALLOC_CAP_8BIT), (unsigned)heap_caps_get_largest_free_block(MALLOC_CAP_8BIT));
                 break;
-            case WIFI_EVENT_AP_STADISCONNECTED:
+            }
+            case WIFI_EVENT_AP_STADISCONNECTED: { /* CP-WIFI-DEBUG */
+                wifi_event_ap_stadisconnected_t *e = (wifi_event_ap_stadisconnected_t *)event_data;
+                ESP_LOGW(TAG, "ap sta disconnected " MACSTR " aid=%d reason=%d", MAC2STR(e->mac), e->aid, e->reason);
                 break;
+            }
             case WIFI_EVENT_STA_START:
                 ESP_LOGW(TAG, "sta start");
                 break;

diff --git a/ports/espressif/esp-idf-config/partitions-8MB-no-ota-no-uf2.csv b/ports/espressif/esp-idf-config/partitions-8MB-no-ota-no-uf2.csv
@@ -0,0 +1,7 @@
+# Name,             Type,   SubType,    Offset,     Size
+# bootloader,       app,    boot,       0x1000/0x0, 28/32K
+# partition_table,  data,   table,      0x8000,     4K
+nvs,                data,   nvs,        0x9000,     20K
+otadata,            data,   ota,        0xe000,     8K
+ota_0,              app,    ota_0,      0x10000,    4032K
+user_fs,            data,   fat,        0x400000,   4096K
diff --git a/ports/espressif/esp-idf-config/sdkconfig-flash-8MB-no-ota-no-uf2.defaults b/ports/espressif/esp-idf-config/sdkconfig-flash-8MB-no-ota-no-uf2.defaults
@@ -0,0 +1,4 @@
+CONFIG_ESPTOOLPY_FLASHSIZE_8MB=y
+CONFIG_ESPTOOLPY_FLASHSIZE="8MB"
+CONFIG_PARTITION_TABLE_CUSTOM_FILENAME="esp-idf-config/partitions-8MB-no-ota-no-uf2.csv"
+CONFIG_PARTITION_TABLE_FILENAME="esp-idf-config/partitions-8MB-no-ota-no-uf2.csv"
diff --git a/ports/espressif/esp-idf-config/sdkconfig-wifidebug-opt.defaults b/ports/espressif/esp-idf-config/sdkconfig-wifidebug-opt.defaults
@@ -0,0 +1,17 @@
+#
+# CP-WIFI-DEBUG (release-optimised variant): keep the opt build's RAM/flash profile but
+# route ESP_LOGW/ESP_LOGE + DHCPS_DEBUG printf to the UART0 console (devkit UART bridge).
+# Use with: make BOARD=... EXTRA_SDKCONFIG=esp-idf-config/sdkconfig-wifidebug-opt.defaults
+#
+# CONFIG_ESP_CONSOLE_NONE is not set
+CONFIG_ESP_CONSOLE_UART_DEFAULT=y
+CONFIG_ESP_CONSOLE_SECONDARY_NONE=y
+# CONFIG_LOG_DEFAULT_LEVEL_NONE is not set
+CONFIG_LOG_DEFAULT_LEVEL_WARN=y
+CONFIG_LOG_MAXIMUM_LEVEL_WARN=y
+# TLS server: a 3.7KB Let's Encrypt chain must fit one outgoing handshake record
+CONFIG_MBEDTLS_SSL_OUT_CONTENT_LEN=4096
+CONFIG_MBEDTLS_SSL_IN_CONTENT_LEN=4096
+CONFIG_MBEDTLS_DYNAMIC_BUFFER=y
+CONFIG_MBEDTLS_DYNAMIC_FREE_PEER_CERT=y
+CONFIG_MBEDTLS_DYNAMIC_FREE_CONFIG_DATA=y
diff --git a/ports/espressif/esp-idf-config/sdkconfig-wifidebug.defaults b/ports/espressif/esp-idf-config/sdkconfig-wifidebug.defaults
@@ -0,0 +1,9 @@
+#
+# CP-WIFI-DEBUG: extra logging for softAP / DHCP / BLE coexistence investigation.
+# Use with: make BOARD=... DEBUG=1 EXTRA_SDKCONFIG=esp-idf-config/sdkconfig-wifidebug.defaults
+#
+# (LWIP_DEBUG / LOG_MAXIMUM_LEVEL_DEBUG / dynamic log control overflow the C6's 2MB
+#  firmware partition by ~186KB -- DHCP server logging comes from DHCPS_DEBUG=1 instead)
+CONFIG_LOG_DEFAULT_LEVEL_INFO=y
+# CONFIG_BT_NIMBLE_LOG_LEVEL_NONE is not set
+CONFIG_BT_NIMBLE_LOG_LEVEL_INFO=y
diff --git a/ports/espressif/supervisor/port.c b/ports/espressif/supervisor/port.c
@@ -32,6 +32,8 @@
 #include "common-hal/watchdog/WatchDogTimer.h"
 #include "common-hal/socketpool/Socket.h"
 #include "common-hal/wifi/__init__.h"
+#include "shared-bindings/wifi/__init__.h"
+#include "shared-bindings/wifi/Radio.h"
 #include "supervisor/background_callback.h"
 #include "supervisor/shared/tick.h"
 #include "shared-bindings/microcontroller/__init__.h"
@@ -50,6 +52,7 @@
 
 #if CIRCUITPY_BLEIO_NATIVE
 #include "shared-bindings/_bleio/__init__.h"
+#include "shared-bindings/_bleio/Adapter.h"
 #endif
 
 #if CIRCUITPY_ESPCAMERA
@@ -342,9 +345,34 @@ void *port_realloc(void *ptr, size_t size, bool dma_capable) {
     return heap_caps_realloc(ptr, size, caps);
 }
 
+// Headroom kept in the IDF heap when the Python heap grows while a radio is
+// enabled. The wifi driver, lwIP and NimBLE allocate at runtime (TX buffers,
+// station association, DHCP replies, ESP-NOW frames); without this the GC heap
+// absorbs the whole system heap and those allocations fail silently
+// (ESP_ERR_ESPNOW_NO_MEM, stations that associate and drop, hard faults).
+#ifndef CIRCUITPY_ESP_RADIO_HEAP_RESERVE
+#define CIRCUITPY_ESP_RADIO_HEAP_RESERVE (40 * 1024)
+#endif
+
 size_t port_heap_get_largest_free_size(void) {
-    size_t free_size = heap_caps_get_largest_free_block(MALLOC_CAP_8BIT);
-    return free_size;
+    size_t largest = heap_caps_get_largest_free_block(MALLOC_CAP_8BIT);
+    size_t reserve = 0;
+    #if CIRCUITPY_WIFI
+    if (common_hal_wifi_radio_get_enabled(&common_hal_wifi_radio_obj)) {
+        reserve = CIRCUITPY_ESP_RADIO_HEAP_RESERVE;
+    }
+    #endif
+    #if CIRCUITPY_BLEIO_NATIVE
+    if (common_hal_bleio_adapter_get_enabled(&common_hal_bleio_adapter_obj)) {
+        reserve = CIRCUITPY_ESP_RADIO_HEAP_RESERVE;
+    }
+    #endif
+    if (reserve == 0) {
+        return largest;
+    }
+    size_t total = heap_caps_get_free_size(MALLOC_CAP_8BIT);
+    size_t allowed = total > reserve ? total - reserve : 0;
+    return MIN(largest, allowed);
 }
 
 void reset_port_early(void) {